Modern passenger vehicles include a heating, ventilation, and air conditioning (HVAC) system that allows a vehicle occupant to control the temperature or adjust other settings of a vehicle interior. For instance, a motor-driven fan or blower circulates conditioned air to the vehicle interior through air vents. Some vehicles are equipped with heated and/or cooled seats, a heated steering wheel, and other features that collectively improve the overall drive experience. A typical HVAC system includes front and rear defrosters for improving visibility through the windshield and rear window, respectively. An occupant of the vehicle selects desired HVAC system settings using dials, knobs, push-buttons, and/or touch screens.